It may be that the version of 7-Zip you are using is an old version and if I remember correcly around the 9.04 area there were two versions of 7-zip, one which used the standard character set and another that was Unicode.

The current version of 7-zip is 9.20, yours appears to be 9.04. Can you update and try again?

There is also a bug report from the p7zip (Unix port of 7-zip) Sourceforge page that claims this was fixed since 9.13, so again I would recommend updating to 9.20 if possible: Sourceforge Bugtracker